Battery powered electric knife

ABSTRACT

A BATTERY OPERATED ELECTRIC KNIFE HAVING AN ELONGATED HOUSING DEFINING THE KNIFE HANDLE AND ENCLOSING AN ELECTRIC MOTOR AND BATTERY UNIT. A PAIR OF CHARGING CONTACTS ARE MOUNTED ENTIRELY WITHIN THE ELONGATED HOUSING WITH ACCESS OPENINGS THERETO AND A CHARGING AND STORAGE STAND ARE PROVIDED SHAPED TO RECEIVE THE KNIFE HANDLE IN ONLY ONE PREDETERMINED POSITION WHEREBY SAID HOUSING FOR THE ELECTRIC KNIFE MAY BE RESILIENTLY CLAMPED IN ASSEMBLED RELATIONSHIP WITH THE CHARGING UNIT. AN IMPROVED PERMANENT MAGNET ROTOR IS EMPLOYED HAVING AN OUTER FIELD MEMBER COMPRISING A RESILIENT CYLINDRICAL SHELL WITH A SLIT THEREIN.

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United States Patent 3,606,216 BATTERY POWERED ELECTRIC KNIFE Worthy L.Chambers, Lombard, Ill., assignor to Sunbeam Corporation, Chicago, Ill.

Original application Aug. 24, 1966, Ser. No. 574,648, now Patent No.3,432,702, dated Mar. 11, 1969. Divided and this application Nov. 12,1968, Ser. No. 775,064

Int. Cl. A47g 21/14 U.S. Cl. 248-373 4 Claims ABSTRACT OF THE DISCLOSUREThis is a division of application Ser. No. 574,648, filed Aug. 24, 1966,now Patent 3,432,702 assigned to the same assignee as the instantapplication.

The present invention relates to an electric knife and more particularlyto a battery operated electric knife. Specifically, the presentinvention is an improvement on copending Cousins et a1. application Ser.No. 532,261, filed Mar. 7, 1966, now Patent 13,417,469.

Electric knives such as disclosed in the above-mentioned copendingapplication have become very popular in recent years and are nowextensively used. Many times it is desired to use an electric carvingknife in a location where power can be supplied thereto only through arather lengthy cord. It would be desirable, therefore, to provide apower operated electric knife which is battery powered whereby a powercord is unnecessary during a carving or slicing operation.

Most of the electric knives presently on the market comprise a pair ofblades releasably secured together and reciprocated by a suitableelectric motor contained in a power unit with the blades moving insliding contact with each other. The blades are readily removable fromthe power unit for cleaning purposes and are securely attached theretowhen used to perform a cutting operation. It is desirable to provide apower operated electric slicing knife which is light in weight, easy tomanufacture and assemble, and wherein means are provided to readilyrecharge the batteries when the knife is not in use. Since a chargingunit is necessary, it would be desirable to have such charging unit alsosupport the blades, after they have been cleaned, in a manner that theuser may readily secure the blades to the power unit without having totouch the blades during this securing operation.

Accordingly, it is an object of the present invention to provide a newand improved battery operated electric knife.

It is another object of the present invention to provide an electricknife which is simple and compact, easy to manufacture and assemble,foolproof in operation and capable of giving many years of satisfactoryservice to the user.

Still another object of the present invent-ion is to provide an improvedelectric motor for driving the blades of an electric slicing knife.

A further object of the present invention resides in the provision of alightweight electric knife which is ice properly balanced, easy tomaneuver by the user, and which readily fits the users hand and iscomfortable to use even though it contains not only an electric motorbut rechargeable batteries for energizing such motor.

A further object of the present invention resides in improved andcompact mounting means for the power and drive mechanisms for anelectric knife so as to permit ready assembly and disassembly and lowmanufacturing cost.

Further objects and advantages of the present invention will becomeapparent as the following description proceeds and the features ofnovelty which characterize the invention will be pointed out withparticularity in the claims annexed to and forming a part of thisspecification.

For a better understanding of the present invention reference may be hadto the accompanying drawings in which:

FIG. 1 is a perspective view of an electric knife embodying the presentinvention with the blades assembled to the power unit so as to be readyfor a cutting or slicing operation;

FIG. 2 is an enlarged longitudinal sectional View taken substantially online 22 of FIG. 1 showing primarily the power unit with only a smallportion of the blades illustrated, and with certain portions cut away toaid in better illustrating the details of the slicing knife of FIG. 1;

I FIG. 3 is a top plan view of the power unit with a portion of the topcover cut away more clearly to illustrate the present invention;

FIG. 4 is an enlarged fragmentary top plan view of the base portiondefining the casing of the power unit with all elements of the slicingknife removed therefrom;

FIG. 5 is a greatly enlarged fragmentary sectional view taken on line5-5 of FIG. 3 (also along line 55 of FIG. 4) more clearly to illustratethe mounting arrangement between the electric motor of the power unitand the casing housing the same;

FIG. 6 is a somewhat enlarged sectional view taken on line S-5 of FIG.2, assuming that FIG. 2 shows the complete structure;

FIG. 7 is an end view of one element of the electric motor best shown inFIGS. 2 and 6;

FIG. 8 is a view looking in the direction of the arrows 8-8 of FIG. 7;

FIG. 9 is an enlarged fragmentary sectional view taken on line 9--9 ofFIG. 2, again assuming that FIG. 2 shows the complete structure;

FIG. 10 is a fragmentary top plan view with certain portions cut away ofthe commutator end of the electric motor employed in the electric knifeof the present invention;

FIG. 11 is a fragmentary rear end view of the electric motor looking inthe direction of the arrows 1111 of FIG. 10;

FIG. 12 is an enlarged front end view of the electric motor andassociated drive mechanism taken substantially on line 12-12 of FIG. 2,assuming that FIG. 2 shows the complete motor and drive structure;

FIG. 13 is a fragmentary sectional view taken on line 1313 of FIG. 4 butassuming the charging contact and associated conductor is in assembledposition in FIG. 4;

FIG. 14 is a top plan view of FIG. 13;

FIG. 15 is an end view of the charging contact looking in the directionof the arrows 15---15 of FIG. 14;

FIG. 16 is a schematic diagram illustrating the electric circuit of theelectric knife of the present invention;

FIG. 17 is a perspective view of the charging and storage unit showingthe electric knife of the present invention as it would normally bestored for recharging;

, FIG. 18 is a fragmentary top view of the storage unit of FIG. 17illustrating how the power unit may be asso ciated with the blades ofthe electric knife without touching the blades;

FIG. 19 is a greatly enlarged fragmentary view of a portion of FIG. 17;and

FIG. 20 is an elevational view of one element shown in FIGS. 17, 18 and19 of the drawings.

Briefly, the present invention is concerned with an electric knifeincluding a two-part casing within which is mounted an electric motorand drive mechanism for converting rotary motion of the armature shaftof the electric motor to counter-reciprocating motion of a pair ofblades disposed in intimate sliding contact with each other. Alsomounted within the casing is a battery unit comprising a plurality ofrechargeable batteries adapted to be readily connected to charging meansand also adapted to energize the electric motor when desired. Im-

proved means are provided for supporting the mechanism within thehousing in a very simple manner, and a powerful battery energizedelectric motor is provided. Cooperating means on the motor and withinthe casing of the power unit of the electric knife serve to hold theparts in assembled relationship including simple means not only forsupporting the charging contacts but for simultaneously completingelectrical connections with such charging contacts.

A combined storage and charging unit is provided which is provided witha cradle portion to readily receive the power unit of the electricknife. By merely inserting the electric knife into the cradle portion,the charging circuit for the rechargeable batteries is completed.Additionally, the charging unit includes a storage section for the knifeblades arranged so that the power unit may be attached to these bladeswhile in the storage unit witl1- out touching the blades in assemblingthem to the power unit.

Referring now to the drawings, there is illustrated a power operatedslicing knife comprising a power unit generally designated as 21 forreciprocating in sliding engagement with each other a pair of knifeblades collectively designated as 22. The knife blades 22 form no partof the present invention and are preferably identical with thosedisclosed in the copending Cousins et al. application referred to above.No further description of the knife blades 22 is, therefore, includedherewith except to point out that the knife blades 22 are provided withrearwardly extending tang portions 22a, best shown in FIGS. 17 and 18 ofthe drawings, which are adapted to be received in suitable blade holders24 (FIG. 2) which form no part of the present invention but arepreferably identical with the blade holders disclosed and claimed in theabove-mentioned Cousins et al. application. When the tang portions 22aof the knife blades 22 are inserted by longitudinal movement of theknife blades 22 into the blade holders 24, the blades 22 are latched indriving relationship with the power unit 21. As in the abovementionedCousins et al. application, the blades 22 are provided with guards 25which again form no part of the present invention but preferably areidentical with those disclosed in the above-mentioned Cousins et al.application.

Considering now the power unit 21 in more detail, it comprises a casingdefined by a base member or base 27 and a cover or cover member 28 whichare adapted to be secured together to define a hollow motor and batterychamber therein. To this end suitable screw-type fastening means 29(FIG. 2) are adapted to extend through openings 30 (FIG. 4) in basemember 27 to engage cooperating tapped openings 31 (FIG. 2) in covermember 28. To secure the front portions of members 27 and 28 together,the former is provided with integral interlocking projections 27a (FIG.2) at the front end thereof receivable in suitable cooperating openings(not shown) defined through a projection or hilt portion 28a at theforward end of the cover member 28. Preferably the.

. base 27 and the cover member 28 are each molded from In order torelease the blades 22 from the power unit 21 once the two are assembledin operative relationship, a pair of blade release buttons '32 areprovided, only one of which is shown in FIG. 1 of the drawings, theother being disposed on the opposite side but in the same positionrelative to the power unit 21. These blade release buttons 32 may beidentical with those disclosed in the copending Cousins et al.application referred to above and form no part of the present invention.They are biased outwardly by a suitable U-shaped biasing spring 33 shownonly in FIG. 2 of the drawings, which spring is prefer- V ably alsoidentical to that disclosed in the above-men tioned Cousins et al.copending application. I

It will be apparent that means must be provided to convert rotary motionof a conventional electric motor to counter-reciprocating motion of thepair of knife blades generally designated as 22. Tothis end there isincluded within the power unit a drive mechanism.

generally designated as 34 which forms no part of the present inventionand preferably is identical with that disclosed in the above-mentionedCousins et al. application. As best shown in FIGS. 2 and 12 of thedrawings, this drive mechanism includes a molded one-piece assemblycomprising a worm gear portion 34a, a pair of eccentrics (not shown)molded on the end faces of the gear 34a and drivingly receiving a pairof connecting rods 35 and 36. The connecting rods 35 and 36 are adaptedto drive a pair of blade holders such as 24. The drive mechanismdescribed forms no part. of the present invention and is preferablyidentical with that disclosed in the above-mentioned Cousins et al.application. Moreover, as described in the above-mentioned Cousins etal. application, the gear 34a and eccentrics are molded onto a suitableshaft 37, the ends of which project beyond the connecting rods 35 andare receivable within suitable journals 38 and 39. Preferably thejournals 38 and 39 are pressed onto the ends of the shaft 37 thusholding the gear 34a and integral eccentrics (not shown), the connectingrods 35 and 36, the shaft 37, and the journals 3 8 and 39 in assembledrelationship in the same manner as described in the abovementionedCousins et al. application.

Also, as described in the above-mentioned Cousins et al. application, inorder selectively to energize the electric motor of the power unit 21described in detail hereinafter, there is provided a switchactuatorortrigger 40 which is pivotally mounted to the forward end ofthe base portion 27 by means of an L-shaped spring 41, a suitable screw42 securing one arm of the L to the end of the trigger. The trigger 40is adapted to be actuated by the finger of the user so as to move thefree end of a movable blade contact 44a into contacting engagement withthe free end of a stationary blade contact 44b, the contacts 44a and 44bdefining a switch 44. As illustrated, the blade contacts 44a and 44b aresupported in spaced parallel relationship on an integral projection 27bof the base 27. Y As illustrated in FIG. 2 of the drawings, a safetymechanism substantially identical with that disclosed in the Cousins etal. application is provided whereby the switch trigger 40 may be lockedagainst accidental operation. To this end a cylindrical finger 45 isprovided which is connected to the trigger 40 by an integral flexibleportion 45a and suitable fastening means 46. The ends of the cylindricalfinger 45 are adapted to engage a pair of spaced recesses defined in apair of spaced downwardly directed projections 27c integrally moldedwith the base 27. The switch 44, the trigger 40, the safety meanscomprising the finger 45, etc. form no part of the, present inventionandare described merely to disclose an operative structure. They arepreferably identical with the corresponding arrangement disclosed intheabove-mentioned Cousins et al..application.

The power unit 21 of. the. present invention includes an electric motorgenerally designated'as 48, best shown in FIGS. 2, 3, 6, 7, 8, 10, 11,12 and 16 of the drawings, and a battery unit generally designated as49, which are described in greater detail hereinafter. As best shown inFIG. '16 of the drawings, the battery unit 49 comprises a plurality ofindividual batteries 49a, 49b, 49c and 49d connected in series with thepositive terminal 50 of the battery unit connected by a conductor 51with thepositive terminal of the motor 48. The negative terminal 52 ofthe battery unit 49 is connected by a conductor 53 to the movable switchterminal 44a of the switch 44. An intermediate portion of this conductor53 is connected to one charging terminal 55 described in greater detailhereinafter. The stationary switch contact 44b in turn is connected by aconductor 56 to the negative terminal of the direct current motor 48.Additionally, the positive battery terminal 50 is connected by aconductor 58 to the negative charging terminal 59. It should beunderstood that the reference numerals employed in the schematic diagramof FIG. 16 are employed for corresponding parts in the other figures ofthe drawings. 6

Considering now the motor 48 best shown in FIGS. 2,

3, 6, 7, 8, 10, 11 and 12 of the drawings, it comprises a low voltagedirect current motor which can be energized from rechargeable batteries,and specifically from the battery unit 49 referred to above. Asillustrated, the motor 48 comprises a cylindrical outer shell60 having alongitudinally extending slit 61 extending from end to end of the shellwhereby the shell 60 might be characterized as a split shell. In orderto orientate the other motor parts relative to the shell 60, the ends ofthe latter are provided with a pair of aligned notches 62 in the endsthereof (FIG. 8), which alignednotches are positioned diametricallyopposite the slit 61. The shell 60 has sufficient inherent resilience totend to close the slit 61 as shown in FIG. 6 of the drawings. When theshell is assembled, as described in detail hereinafter and as shown inFIG. 6 of the drawings, the slit 61 is increased in width. 'Disposedimmediately within the shell 61 and in intimate contact therewith is asheet of molded material 64, preferably formed of barium ferrite or thelike, which is commonly termed a flexible permanent magnet. Disposedinside the magnet 64 are a pair of diametrically opposed pole shoes 65anl 66. The inherent resilience of the outer shell 60 tends to make goodcontact between the shell 60 and the magnet 64, and also between themagnet 64 and the pole shoes 65 and 66, which is important. Asillustrated in FIG. 6 of the drawings, the slit 61 in the outerresilient shell is disposed in alignment with the center of one of thepole shoes (specifically pole shoe 66), and the slit defined between theends of the magnet 64, designated as 67, is disposed at an angle of 90relative to the slit 61.

In order to define an accurate air gap between the pole shoes 65 and 66and the armature 69 of the motor 48 in a simple and inexpensive manner,a pair of molded motor end mmebers 70 and 71 are provided. These membersmay be molded from a suitable plastic material. The end member 70 isdesignated as the commutator end member, while the end member 71 isdesignated as the drive'mechanism end member. Each of the end membersv70 and 71 is provided with a projection having accurately formedexternal cylindrical surfaces to engage and accurately position theinnercorresponding arcuate surfaces of the pole shoes 65 and 66 therebydefining by a simple manufacturing process without any machining a veryaccurate air gap between the armature 69 and the pole shoes 65 and 66.It will be understood that the inherent resilience of the outer shell intending to close the slit 61 clamps the magnet 64 which in turn forcesthe pole shoes and 66 into clamping engagement with the projections onmembers and 71 having accurately formed external cylindrical surfaces,thus accurately determining the air gap and at the same time insuringgood contact between the clamping sleeve 60 and the cylindrical flexiblemagnet 64, and also between the magnet 64 and the pole shoes 65 and 66thereby maintaining the magnetic reluctance of the magnetic circuit ofthe motor 48 as low as possible. Specifically, and to this end, endmember 70 is provided with a discontinuous cylindrical projection 70ahaving a pair of diametrically opposed notches (not shown) definedtherein. This projection 70a has portions engaging the pole shoes 65 and66, as clearly shown in FIG. 2 of the drawings. Similarly, end member 71is provided with a cylindrical projection 71a engaging the pole shoes 65and '66, as shown in FIG. 2.

For the purpose of angularly spacing the pole shoes 65 and 66 from eachother, as shown in FIG. 6 of the drawings, each of the projections 70aand 71a is provided on the cylindrical surfaces referred to above withdiametrically disposed radial projections receivable in the gaps betweenthe pole shoes 65 and 66, only portions 71 of the projection 71a beingclearly visible in FIG. 6 of the drawings. Also, end member 71 isprovided with a projection 71g receivable in one of the notches 62 inthe ends of sleeve 61 as shown in FIG. 8. A similar projection isprovided on end member 70 to engage the other notch 62. With the abovedescribed arrangement the parts of the motor stator and end members areproperly orientated initially during the assembly operation and remainso. Also, as illustrated, the end member 70 includes an annular portion70b for mounting therein a bearing 72 to support the commutator end ofan armature shaft 73 upon which is supported the armature 69. Similarly,the end member 71 is provided with an annular portion 71b for supportinga ball bearing assembly 74 thereby to rotatably support the other end ofthe armature shaft 73.

In accordance with the present invention, end member 71 also functionsas a mounting means for the drive mechanism and, to this end, isprovided with an integral forwardly extending U-shaped projection 71cbest shown in FIGS. 2, 3, 5 and 12 of the drawings. This projection 71cis open at the top and open at the front end, which is the end mostremote from the annular portion 71b of end member 71. Moreover, theprojecting end of armature shaft 73 extends into the upper part of thechamber formed by the U-shaped projection. The bight of the U- shapedprojection 71c is disposed closely adjacent the base member 27, whilethe sides of the U-shaped projection 71c extend upwardly on either sideof drive mechanism 34, as best shown in FIG. 12 of the drawings. Tosupoprt the journals 38 and 39, these side portions are recessed toprovide journal receiving grooves 77 and 78 (FIGS. 5 and 12) to receivetherein the journals 38 and 39. With this arrangement the drivemechanism 34, comprising the Worm gear 34a, the integrally moldedeccentrics on either face thereof, the connecting rods 35 and 36, andthe shaft 37 to which the journals 38 and 39 are press fitted, isinserted into the open front end of U-shaped projection 71c, with thejournals 38 and 39 inserted into the grooves 77 and 78, respectively. Tohold the drive mechanism in position, suitable bearing retainers 80 areprovided, the ends of which bite into the walls defining the upper andlower edges of the grooves. As illustrated, the side walls of theboxlike projection 71c defining the grooves 77 and 78 are provided withrectangular recesses 81 (FIGS. 5 and 12) to receive a suitable thrustpad 82 engageable by one end of shaft 37 to take the end thrust thereof.

In order that the motor 48 is drivingly related to the drive mechanism34, the armature shaft 73 extends into the chamber defined by theU-shaped projection 71c and is provided with a suitable worm 83 whichoverlies worm gear 34a and meshes therewith.v

. The end member 70, best shown in FIGS. 2, 3, and 11 of the drawings,includes the annular portion 7017 mentioned above for supporting thebearing 72, which bearing is held in position by a suitable bearingretainer 85. The bearing retainer 85 is an annular member having a pairof diametrically opposed projecting ears 85a (FIG. 11). The annularportion 70b of end member 70 is provided with diametrically opposedopenings 86 to permit the insertion therein of the ears 85a of bearingretainer 85. These ears are insertible into annular portion 70b byvirtue of the discontinuities referred to above in the projections 70a,the ears being adapted to extend into thespace provided by thesediscontinuities during the assembly operation. After the retainer 85 hasbeen moved into retaining engagement with hearing 72, it is rotatedthrough a slight angle from its position with ears 85a in openings 86 tothe position shown in FIG. 11 of the drawings thereby to retain thebearing 72 in position without any additional fastening means.

As best shown in FIGS. 2 and 10 of the drawings, a commutator 87 issupported on shaft 73 within the end member 70, and suitable commutatorbrushes such as 88 are longitudinally movable in cooperating recesses 89defined at diametrically'opposed positions in end member 7 0. Suitablesprings 90 bias the brushes into contacting engagement with thecommutator 86. As best shown in FIG. 16 of the drawings, conductors 51and 56 are electrically connected to the brushes 88. To permit readyaccess to the brushes 88 and the springs 90, removable brush clips 92are provided which are sort of fork-shaped members which slidably engageprojections 70d on the end member 70.

In order to hold the end members 70 and 71 in assembled relationshipwith the concentrically disposed sleeve 60, flexible magnet 64 and poleshoes 65 and 66, there are provided a pair of clamp members 94, bestshown in FIGS. 3, 6, 10, 11 and 12 of the drawings, which are disposedoutside sleeve 60 in diametrically opposed positions and which clamp theend members to sleeve 60. These clamp members 94 each include ahook-shaped end 94a for engaging a suitable opening such as 95 (FIGS. 6and 12) in end member 71, while the other end of each clamp is providedwith a latching. portion 94b (FIGS. 10 and 11) for engaging with asuitable depression 96 in the end member 70 (FIG. 11).

For the purpose of securing the motor 48 in position within thebasemember 27 in a simple and inexpensive manner, the base member 27 isprovided toward its forward end with a pair of spaced elongated openings97 (FIGS. 4 and 5). These openings are surrounded by upwardly directedwall'portions 27d (FIGS. 4 and 5) integrally formed with base member 27.Overlying the forward end of each opening 97 is a somewhat hook-shapedportion 27e, the underside of which is level with the top of wallportions 27d. Integrally molded with end member 71 and depending inspaced parallel relationship from the underside of the bight portion ofprojection 710 are a pair of rail portions 71d of a width so as toslidably fit within openings 97. Rail portions 71d include end portionsprojecting forwardly of the bright portion of projection 710 to bereceived beneath hook-shaped portions 27e as best shown in FIG. 5 of thedrawings. Moreover, the underside of the bight portion of projection 71crests on the top of wall portions 27d thus firmly securing the motor 48against movement relative to base portion 27 other than upward movementof the commutator end thereof pivoted about the hook-shaped portions27e. In order to hold down the commutator end of the motor against suchpivotal movement, there is supported in cover member 28 a motor anchorspring 98 (FIGS. 2 and 6) supported by projecting fingers 28b integrallyformed with cover member 28. When the members 27 and 28 are secured inassembled relationship, as shown in FIG. 6 of the drawings, the anchorspring .98.is distorted by engagement with sleeve of the motor in placewhich is particularly advantageous from an assembly and disassemblystandpoint.

To hold the conductors such as 53, 56 and 58 in position, the end memberis provided with a narrow upwardly directed flange 700 having spacednotches 99 and 100 (FIGS. 3 and 10) defined therein. Similarly, endmember 71 is also provided with a narrow upwardly directed flange 712(FIGS. 3 and 12) having spaced notches 101 and 102 therein, the notches100 and 102 being in alignment and receiving conductors 53 and 56therein, and the notches 99 and 101 being in alignment and receivingconductor 58 therein.

In accordance with the present invention, the charging contacts 55 and59 are of a' construction so as to readily cooperate with the basemember 27 and not only be positioned in proper position to cooperatewith an associated charging unit described hereinafter but also readilyto complete electrical connections with conductors 53 and 58 in a singlemanner. The charging contacts 55 and 59 are best shown in FIGS. 2, 3, 6,13, 14, 15 and 16 of the drawings. In order to provide a simple meansfor assemblin-g these contacts with the base member 27, the latter isprovided with a pair of contact receiving openings 103 (FIGS. 4 and 6)in the underside thereof, which openings on the side within the casingdefined in part by base member 27 are partially surrounded by anupstanding U-shaped wall portion 27g. Adapted to be received through theopenings 103 are male-type charging contacts designated as 104 and shownin FIG. 18 of the drawings. The charging contacts'55 and 59' areidentical and hence only one will be described in detail, namely, thecharging contact 55 which is shown in FIGS. 2, 3, 13, 14 and 15 of thedrawings. As best shown in the drawings, this charging contact comprisesa folded over conducting member having a pair of. forwardly directedspring fingers 55w terminating at the free ends of the finger-s with anarrow portion 55b. These fingers 55a are resiliently biased toward eachother so as to make good electrical contact with the contacts 104associated with a storage charging unit when inserted therebetween. Thefingers 55a on the underside thereof, as viewed in FIG. 13 of thedrawings, diverge apart at the lower edge to insure ready insertion ofthe male-type charging contacts 104. The ends of the fingers 55a remotefrom the narrow projections 55b are secured to a U-shaped portion 55cwhich is adapted to receive between the legs thereof a projection 27h(FIGS. 4 and 13) disposed adjacent the forward end of each opening 103.The projections 27h are integrally formed with the base member 27 andinclude at the forward end thereof, as best shown in FIG. 13, aforwardly directed narrow projection 27i. In order to cooperate withprojection 27i, charging contact 55 includes at the end of U-shapedportion 550 remote from fingers 5511 a clamping portion 55d, best shownin FIG. 15, which is adapted to almost completely surround projection27i. In assembling the charging contact 55 to the base portion 27, thebight portion 55c is positioned to receive the projection 27h thereinwith the spring fingers extending into the openings 103 defined betweenwall portions 27g. The wall portion 27g is somewhat U-shaped with theportion thereof remote from projection 27h overlying the end of theopening 103. This overlying portion is designated as 27j, best shown inFIGS. 4 and 13 of the drawings. With the charging contact 55 in theinserted position, it is slid to the left as viewed in FIG.

shaped portion is .a slight projection 27k. It will be understood thatan intermediate portion 'ofconductor .53 will .be inserted in the.V-shaped portionof one. of the projections 27h before the chargingcontactSS-is placed in position,'whereupon the conductor will be clampedbetween theportion 550 of thechargingcOntact.55 and the V-shaped surfaceof thelcooperating-projection 27h, the projection 27k insuring-that theconductor will not be pulledout. The .sameassembly operationis-perfonmed with respect to chargingcontact 59 except thatoneendof'conductor 58 is placed in the V-shaped top of associated projection27h. With this arrangeme'ntitis 'apparout that a very simple assemblyoperation is involved in mounting the'charging contacts in base member27 and simultaneously making-electricalconnection with thec'onductor's53 and58." As-best shown in FIG. 4 of the drawings, the*base member 27 includes integrally for-medcross rib portions, such as27m, -27r'1 and the-like, which provide rigidity and support. In orderthat electrical connections can readily extend beneath the'moto'r48 tothe switch 44 mounted at the forwardwportion of .the motor andparticularly to accommodate leads 53 and .56, the rib portions; such as27m and 2711, are provided. with notches such as 106' and 107, bestshown in FIGS. 2 and '4 of the drawings.

Referring now to the battery unit 49, it comprises a battery rack 110preferably formed of a molded material so as to provide fourcompartments for rechargeable nickel cadmium cells 49a, 49b, 49c and49d, as best shown in FIGS. 2, 3 and 9 of the drawings.- As wasmentioned earlier and as is clearly illustrated in the schematic diagramof FIG. 16 of the drawings, these batteries are connected in series. Tothis end and as best shown in FIG. 9 of the drawings, a conducting strip111 connects the positive terminal of battery 49a to the negativeterminal of battery 49b. Likewise, a conducting strip 112 connects thepositive terminal of battery 490 to the negative terminal of battery49d. At the other end of the cells, not shown in the drawings, thepositive terminal of battery 49b is connected to the negative terminalof battery 49c by a similar suitable conducting strip. Preferably strips111, 112, etc. are soldered directly to the cell terminals. Thus thenegative terminal of battery 49a becomes the terminal 52 of the batteryunit and the positive terminal of battery 49d becomes the positiveterminal 50 of the battery unit, as clearly shown in FIG. 16 of thedrawings, and these terminals are connected as already described inconnection with FIG. 16 of the drawings. Preferably, the base portion 27to the rear of the openings 30 is provided with a pair of spacedconcavities 115 (FIGS. 4 and 9) to receive therein the lowermost cells49b and 4-90.

Referring now to the charging and storage unit, best shown in FIGS. 17,18, 19 and 20, it comprises a somewhat L-shaped housing 118 having abase portion 118a and an upstanding wall portion 11 8b. Within theportion 118a is mounted a suitable transformer and rectifier unit,whereby electric power supplied to the unit 118 through power cord 119may be converted to low voltage direct current supplied to the contacts104 (FIG. 18.). The upper surface of base portion 11 8a of the chargingunit 118 defines a cradle including a recess 121 shaped to receive thepower unit 21 therein, as best shown in FIG. 17 of the drawings. Whenthe power unit is placed into the recess 121 as shown in FIG. 17 of thedrawings, the charging contacts 55 and 59 thereof are electrically engaged with the contacts 104 in a manner readily apparent to thoseskilled in the art.

In order to store the blades 22 in the charging unit 118, the upstandingrear portion 11'8b is provided with a narrow elongated blade receivingrecess 122 so that substantially all of the blades 22, except for theguards 25 and tang portions 22a are received therein. The rear of theupstanding wall portion 11% is recessed as indicate'd at 124, so thatthe user may readily grasp the power unit 21, as shown in FIG. 18 of thedrawings, and move it toward the tangs 22a so that not only are the.tangs received inthe opening in -hilt portion 28a but the tang portionsare receivedinto latching engagement with the blade holders 24. Theoperator can then remove the assembled .power. unit 21and blades=22without having to touch the blades, they being retained in the narrowslot 122 during this assembly operation, i

It will be understood that the blade holders 24 will be" in variousrelative positions in the power unit 21 when it is desired to assemblethe-power unit with the blades 22, and to this end there is provided ablade stop 128 (FIGS. 18, 19, and 20) pivotally mounted in the recess124. This blade stop has a pair of upwardly extending fingers 128a toreceive therebetween theblades 22. These [fingers are engageable by theguards 25 so thatwhichever blade holder first engages the cooperatingknife blade itwill pivot the blade stop 128a and cause the other fingertoposition' the other; blade in the same relative position as the otherblade holder. w [To highlight-some of the less" obvious advantages ofthe invention reference will be made back to-some of the structuraldetails and the advantages associated with them. The construction andorganization of the electric motor 48 and the drive mechanism 34 withthe housing provides significant manufacturing economies while alsoproducing functional advantages. By supporting the drive mecha nism onan integral extension on the motor and member 71, there is provided anarrangement in which the important tolerances between the amature shaftand the drive mechanism may be easily and accurately maintained.

Since the tolerances between the drive mechanism and the blade holdersare not too critical because of their being drivingly related byconnecting rods, the base member 27 which supports the various elementsof the knife may be made of a fairly light, inexpensive plasticmaterial.

-It should also be noted that the bearing used in the end member 71 is aball bearing 74 which also receives the thrust forces delivered to thearmature shaft. By having the thrust bearing 74 included in the endmember which also supports the drive mechanism, the tolerance problemsare further reduced.

With respect to the arrangement of the charging contacts 55 and 59within the housing of the power units 21, it should be appreciated thatthe contacts 55 and 59 are completely out of sight and substantiallyinaccessible by normal means as positioned therein. As a consequence,the male charging terminals must extend a substantial distance to enterthe housing and make contact with the charging contacts. Since anelectric knife is frequently used in the kitchen where food andsilverware are present, it is important to have the contacts recessed inthis manner. Otherwise food may corrode the contacts and prevent goodengagement for charging and inadvertent engagement of the contacts withsilverware could result in discharge of the batteries. Accordingly, therecessed terminals have many advantages from an esthetic and afunctional standpoint.

In view of the detailed description included above, the operation of theelectric knife of the present invention will readily be understood bythose skilled in the art and no further description is includedherewith. Moreover, while there has been illustrated and described aparticular embodiment of the present invention, it will be apparent tothose skilled in the art that various changes and modifications may bemade without departing from the invention in its broader aspects, and itis, therefore, contemplated in the appended claims to cover all suchchanges and modifications as fall within the true spirit and scope ofthe invention.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:

1. A supporting a stand for an electric knife of the type having a powerhandle and a pair of knife blades detachable from said power handle andsecured together for relative reciprocation in engagement with eachother, comprising a base portion having an elongated recess forreceiving and supporting said power handle, a raised blade supportingportion connected to said base member and being formed with a narrowelongated slot adapted to receive and support said blade members, apivotally mounted :blade orientating lever positioned at one end of saidslot, said lever having stops engageable with said blades to restrainsaid blades against longitudinal movement as said power handle isassembled to said blades, the pivotal axis of said lever beingpositioned between said stops so that said lever will shift said bladesrelative to each other to permit assembly to said power handle.-

2. The electric knife supporting stand of claim 1 wherein said elongatedslot receives the cutting portions of said blades, said blades includingmounting tangs which detachably secure said blades to said power handle,said tangs extending beyond said stops into a clearance opening providedon said stand when said cutting portions are received in said slot, saidclearance opening permitting said power handle to be assembled to thetangs of said blades while said blades are received in said slots.

3. A blade storage unit for a pair of knife blades secured together forrelative reciprocating movement each blade being of the type having acutting portion and a tang portion, the tang portions beingsimultaneously receivable in adjacent blade holders in an electric powerhandle said cutting portions received within said slot, and en largedrecess into which said tang portions of said blades extend formed insaid support at one end of said slot, a blade stop pivotally mounted onsaid support at one end of said slot, means on said stop engaging eachof said blades to-rotate said stop to position said tangs so they may beassembled to said blade holders without removing said blades from saidslot, said enlarged recess providing clearance for said power handle tobe assembled -to the tangs of said knife blades while positioned in saidslot.

4. The blade storage unit of claim 3 wherein said blade stop comprises atransversely extending member pivoted about its midpoint and havingupwardly extending fingers between which said blades are received,laterally extending means on said blades engagingsaid fingers on theside toward the blade tangs to adjust the relative position of saidblades on assembly to said power handle. 1

References Cited UNITED STATES PATENTS 2,357,646 9/1944 Gilbert 24837.63,292,885 12/1966 Stephens 24837.3

ROBERT C. RIORDON, Primary Examiner J. C. PETERS, Assistant Examiner US.01. X.R. 320-2; 30-296

